For example, a multilayer ceramic capacitor is used in a variety of electronic equipment because of high reliability and low cost thereof. Specifically, the multilayer ceramic capacitor is used in information terminals, home electronics, automobile electronic components, and the like.
In these use applications, particularly, in a multilayer ceramic capacitor for use application of in-vehicle use or the like, as compared to a typical multilayer ceramic capacitor, securement up to a higher-temperature region is required in some cases and a higher reliability is necessary. It is necessary that the multilayer ceramic capacitor is not broken against a voltage to be applied, that is, has a high breakdown voltage. Further, in the environment in which a high voltage is applied as described above, in order to obtain a large capacitance, a change in specific permittivity when a DC voltage is applied (hereinafter, described as DC bias characteristics) is required to be small.
Patent document 1 discloses a technology relating to a tungsten bronze type composite oxide exhibiting a high specific permittivity and high specific resistance.
However, since an alkali metal element is contained as a constituent element and has high volatility, there is a problem in that handling at the time of manufacturing is prone to be cumbersome, for example, a process of filling an alkali metal element needs to be introduced in processes.
Further, since a defect caused by potassium with high volatility easily occurs in the dielectric composition and thus a conduction electron is easily generated, there is a problem in that a high breakdown voltage is difficult to obtain.
Further, patent document 2 discloses a technology relating to a perovskite type oxide having high voltage resistance at 150° C.
However, since the perovskite type oxide has a low specific permittivity in a high-temperature region of 175° C. or higher that is expected to be used hereafter, there is a problem in that a desired capacitance is difficult to obtain.
Further, non-patent document 1 discloses a technology relating to a tungsten bronze type dielectric Ba2MTi2Nb3O15 (M=Bi3+, La3+, Nd3+, Sm3+, Gd3+) with a high specific permittivity and a small dielectric loss. The tungsten bronze type dielectric has a high specific permittivity at room temperature of about 100 to 700 and a favorable value of tan δ at room temperature of 5% or less. In addition, non-patent document 2 discloses a technology relating to a tungsten bronze type dielectric Ba2Sm2Ti4Ta6O30 with a high specific permittivity and a small dielectric loss. The tungsten bronze type dielectric has a high specific permittivity at room temperature of about 120 and a favorable value of tan δ at room temperature of 3% or less.
Further, regarding DC bias characteristics, patent document 3 and patent document 4 disclose a technology of decreasing DC bias characteristics using a BaTiO3-based material having a high specific permittivity as a ceramic composition.
However, any of the patent documents and the non-patent documents do not mention properties and voltage resistance which are secured up to a high-temperature region of 175° C. or higher that is expected to be used hereafter. Further, in the ceramic compositions disclosed in the patent document 3 and the patent document 4, when a DC voltage applied to the electronic component becomes higher, a change in capacitance is not sufficiently suppressed. In particular, in a case where a DC voltage with high field strength of 5 V/μm or more is applied to the ceramic composition, a problem arises in that the specific permittivity is decreased by 30% or more. It is urgent to solve such problems in consequence of high breakdown voltage of an in-vehicle module in recent years, and in a multilayer ceramic capacitor for use application of in-vehicle use or the like, higher voltage resistance and further favorable DC bias characteristics are required.